Editing Longwall mining (section)

==Layout==
{{multiple image
   | width     =200
   | direction =vertical
   | image2    = AdvancingLongwall.png
   | alt2      = Plan of longwall mine
   | caption2  = Oklahoma advancing longwall mine c.&nbsp;1917; arrows show airflow
   | image1    = RetreatingLongwall.png
   | alt1      = Plan of longwall mine
   | caption1  = West Virginia retreating longwall mine c.&nbsp;1917
  }}
Gate roads are driven to the back of each panel before longwall mining begins. The gate road along one side of the block is called the maingate or headgate; the road on the other side is called the tailgate. Where the thickness of the coal allows, these gate roads have been previously developed by continuous miner units, as the longwall itself is not capable of the initial development. The layout of longwall could be either "advancing" type or of "retreat" type. In the advancing type, the gate roads are formed as the coal face advances. In thinner seams the advancing longwall mining method may be used. In the retreat type, the panel is a face connecting them both. Only the maingate road is formed in advance of the face. The tailgate road is formed behind the coal face by removing the [[stone]] above [[coal]] height to form a roadway that is high enough to travel in. The end of the block that includes the longwall equipment is called the face. The other end of the block is usually one of the main travel roads of the mine. {{Anchor|Goaf|Goff|Gob}}The cavity behind the longwall is called the goaf, goff or gob.<ref>{{cite web |title=Longwall Mining, Underground Coal Mining, Mining Techniques, Mining Companies |url=https://www.greatmining.com/longwall-mining.html |website=Great Mining |accessdate=1 February 2019}}</ref>